function fn1() {
    console.log(`1111 start`);
    fn2();
    console.log(`1111 end`);
}

function fn2() {
    console.log(`2222 start`);
    fn3();
    console.log(`2222 end`);
}

function fn3() {
    console.log(`3333 start`);
    console.log(`3333 end`);
}

fn1();
